OBD is a system that assesses and monitors the performance of engine components, emissions controls and sensors, and the car computer itself, and communicates its findings to the technician by means of diagnostic trouble codes.

The intent of OBDII systems is to ensure proper emission system operation for vehicles and light trucks during their lifetime by monitoring emission-related components and systems for malfunction and/or deterioration. An important aspect of OBDII is its ability to notify the driver of a problem before the vehicle’s emissions have increased significantly by illuminating the “check engine light”. If the vehicle is taken to a repair shop in a timely fashion, it can be properly repaired before any significant emission increase occurs. OBDII systems also provide automobile manufacturers with valuable feedback from their customers’ vehicles that can be used to improve vehicle and emission control system designs.

OBDII systems are designed to alert drivers when something in the emission control system begins to deteriorate or fail. Early diagnosis followed by timely repair can often prevent more costly repairs on both emission control systems and other vehicle systems that may affect vehicle performance such as fuel economy. For example, a poorly performing spark plug can cause the engine to misfire, a condition sometimes unnoticed by the driver. This engine misfire can, in turn, quickly degrade the performance of the catalytic converter. With OBDII detection of the engine misfire, the driver would be faced with a relatively inexpensive spark plug repair. However, without OBDII detection, the driver could be faced with an expensive catalytic converter repair in addition to the spark plug repair. Furthermore, manufacturers have increased incentive to build higher-quality vehicles with better performance, reduced emissions, and more efficient powertrains to prevent problems that can lead to OBDII detection. OBDII systems also provide far more information than ever before to help auto technicians diagnose and properly repair vehicles during their first visit to the repair shop, saving time and money for consumers.

The rule of thumb when it comes to emissions-related vehicle repair is that any modification that changes the vehicle from a certified configuration to a non-certified configuration is considered tampering: this applies to both vehicle owners and repair facilities and is, therefore, a Federal offense. Replacing a catalyst with a straight pipe is one traditional example of tampering. Likewise, overriding the OBDII system through the use of high-tech defeat devices, non-certified computer chips, etc., would also be considered tampering. The OBDII system may, however, be repaired back to its original certified configuration with certified “performance chips” or appropriate aftermarket parts.

Federal law requires that the emission control systems on 1995 and newer model year vehicles be warranted for 2 years or 24,000 miles. Many automakers provide extended warranty coverage beyond what is currently required by federal law. The Federal Clean Air Act requires that catalytic converters and Onboard Diagnostic devices on 1995 and newer vehicles be warranted for a minimum of 8 years or 80,000 miles. If you have questions, contact the automobile dealer or the vehicle manufacturer. Manufacturer contact information and warranty information can be found inside your vehicle owner’s manual.

If you own a 1996 and newer vehicle (20 most current model year vehicles, beginning December 1, 2019) registered in one of the above counties, an annual OBD “emissions” inspection along with a safety/tamper inspection is required.
In these counties, an annual emissions inspection is required for gasoline-powered-light-duty vehicles (less than 8,501 lbs. Gross Vehicle Weight Rating (GVWR)). The GVWR rating can be found on the driver’s side door.
An annual safety inspection only is required if you own a vehicle 1995 and older (vehicles older than the most current 20 model years, beginning December 1, 2019), diesel powered, powered by alternative fuels without gasoline, or a heavy-duty vehicle (greater than 8501 lbs. gross vehicle weight rating (GVWR)). The safety inspection also includes a visual check for tampering of emissions components.
Things to remember:

  • A vehicle’s model year is the year your vehicle was built as designated by the vehicle manufacturer.
  • Motorcycles, recreational vehicles (RVs) and motor homes do not require emissions inspections for registration.

The maximum annual fee for the motor vehicle emissions inspection and safety inspection is $30, however, inspection stations can charge less.

Inspection stations receive most ($23.75) of the total fee for the safety and emissions inspection. The remainder of the fee ($6.25) goes to support various related state programs, including oversight for emissions inspections, the highway trust fund, air quality, and emergency and rescue squads

You will be allowed to register the vehicle without an inspection. When your next annual registration renewal is due, you must have the vehicle inspected to renew your registration. For registration details refer to the following DMV webpage.

You may obtain an inspection and renew your registration up to 90 days prior to the expiration of the vehicle inspection/registration due date. If the length of the vacation is longer than 90 days, you should contact NC-DMV Headquarters for additional information at 1-877-421-0020.

New vehicles will receive a safety/tamper inspection for the first year. “New motor vehicle” means a motor vehicle that has never been titled before. Vehicles registered in an emission county must receive an emissions inspection in the second year of ownership.

Vehicles older than 35 years are not required to receive inspections in any county.

Some kit cars and custom vehicles are exempt from vehicle inspections. For additional information on the definition of what a kit car or custom vehicle is, please contact NCDMV.

Hybrid and plug-in hybrid vehicles that have a gasoline engine are required to receive an annual emissions inspection if registered in an emissions county. Battery electric vehicles will only receive a safety-only inspection. Please contact NC DMV for further information 1(877)421-0020.

Yes, out-of-state registered vehicles may be inspected in North Carolina. There are people who reside in North Carolina on a temporary basis (college students, military personnel, people on business, etc) that may need to renew vehicle registrations or emissions inspections and can not return to their home state in time to have the test completed. In these situations, you will need to have a valid and current registration from your home state. Local inspection stations are found on the DMV’s website.

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